1. Field of the Invention
The present invention relates to a spectroscopic analyzing apparatus and method. More particularly, the present invention relates to a method and apparatus for improving a resolution of a time-varying spectrum.
2. Description of the Related Art
In a spectroscopic analyzing method, light is projected onto a specimen and a reference material, respectively. The respective detected spectrum amplitudes are compared, and the components of the specimen are analyzed. In reviewing an entire spectral band of a specimen, a main component of the specimen has a meaningful spectrum, which is isolated from the remaining components. By analyzing the amplitude of this meaningful spectrum, the components of the specimen and the content of each of the components can be estimated.
One conventional spectroscopic analyzing method uses infrared radiation from a lamp passing through selected filters so that a specific frequency of radiation is incident upon a sample. A photocell detects the reflected signals, and the detected signals are amplified and output through an amplifier. A gain error of the amplifier is compensated for with a sample and hold circuit. However, each channel has its own corresponding sample and hold circuit. Thus, as the number of channels increases, fabrication cost of the spectral analysis system increases.
In another conventional spectroscopic analyzing method, a spectrum is detected using a plurality of amplifiers. The plurality of amplifiers complicates the system, and the addition of channels causes the overall operating costs to be increased. Also, since each of the plurality of amplifiers has a gain error, the accuracy of the analysis is reduced.
If the spectral amplitude of a specimen being analyzed has a constant size, a spectrum may be readily analyzed by amplifying an optical signal. However, if the spectral amplitudes of the specimen vary across the spectrum, the signal-to-noise ratio (SNR) may not be sufficiently high to analyze the entire spectrum. Accordingly, analysis of that specimen component should be abandoned or another wavelength should be selected.
Hence, it is difficult to spectroscopically analyze detected spectra when the detected spectra have large amplitude differences across the spectra, a method for adaptively enhancing the resolution of the spectra to allow the spectra to be easily analyzed is required.